The present invention generally relates to material displacement apparatus and, in a preferred embodiment thereof, more particularly relates to apparatus for releasably coupling a replaceable excavation tooth point to an associated adapter nose structure.
A variety of types of material displacement apparatus are provided with replaceable portions that are removably carried by larger base structures and come into abrasive, wearing contact with the material being displaced. For example, excavating tooth assemblies provided on digging equipment such as excavating buckets or the like typically comprise a relatively massive adapter portion which is suitably anchored to the forward bucket lip and has a reduced cross-section, forwardly projecting nose portion, and a replaceable tooth point having formed through a rear end thereof a pocket opening that releasably receives the adapter nose. To captively retain the point on the adapter nose, aligned transverse openings are formed through these interengageable elements adjacent the rear end of the point, and a suitable connector structure is driven into and forcibly retained within the aligned openings to releasably anchor the replaceable tooth point on its associated adapter nose portion.
These connector structures adapted to be driven into the aligned tooth point and adapter nose openings typically come in two primary forms--(1) wedge and spool connector sets, and (2) flex pin connectors. A wedge and spool connector set comprises a tapered spool portion which is initially placed in the aligned tooth and adapter nose openings, and a tapered wedge portion which is subsequently driven into the openings, against the spool portion, to jam the structure in place within the openings in a manner exerting high rigid retention forces on the interior opening surfaces and press the nose portion into a tight fitting engagement with the tooth socket.
Very high drive-in and knock-out forces are required to insert and later remove the steel wedge and typically require a two man effort to pound the wedge in and out--one man holding a removal tool against an end of the wedge, and the other man pounding on the removal tool with a sledge hammer. This creates a safety hazard due to the possibility of flying metal slivers and/or the second man hitting the first man instead of the removal tool with the sledge hammer. Additionally, wear between the tooth/adapter nose surface interface during excavation use of the tooth tends to loosen the tight fit of the wedge/spool structure within the tooth and adapter nose openings, thereby permitting the wedge/spool structure to fall out of the openings and thus permitting the tooth to fall off the adapter nose.
Flex pin structures typically comprise two elongated metal members held in a spaced apart, side-by-side orientation by an elastomeric material bonded therebetween. The flex pin structure is longitudinally driven into the tooth and adapter nose openings to cause the elastomeric material to be compressed and resiliently force the metal members against the nose and tooth opening surfaces to retain the connector structure in place within the openings and resiliently press the adapter nose portion into tight fitting engagement with the interior surface of the tooth socket.
Flex pins also have their disadvantages. For example, compared to wedge/spool structures they have a substantially lower in-place retention force. Additionally, reverse loading on the tooth creates a gap in the tooth and adapter nose openings through which dirt can enter the tooth pocket and undesirably accelerate wear at the tooth/adapter nose surface interface which correspondingly loosens the connector retention force. Further, the elastomeric materials typically used in flex pin connectors are unavoidably subject to deterioration from hot, cold and acidic operating environments. Moreover, in both wedge-and-spool and flex pin connector structures relatively precise manufacturing dimensional tolerances are required in the tooth point and adapter nose portions to accommodate the installation of their associated connector structures.
It can be seen from the foregoing that it would be desirable to provide improved excavating tooth connector apparatus that eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages associated with conventional excavating tooth and other material displacement equipment connector apparatus of the general type described above. It is accordingly an object of the present invention to provide such improved connector apparatus.